1. Field of the Invention
The invention relates to extracting hydrocarbons from oil-containing rock and sand and more particularly refers to a new and improved process for the recovery of hydrocarbons from oil sands and oil shale involving low temperature carbonization with hydrogenation.
2. Description of the Prior Art
Considerable reserves of crude oil are stored in oil sands and oil shale. The extraction of oil from these reserves is associated with, amongst other things, high costs for separating the oil from sand or shale. Endeavours are being made, therefore, to develop the technical processes necessary for the hydrocarbon extraction, more advantageously in respect of the mode of operation, use of material and energy comsumption.
In a known method of extracting oil from oil sand or oil shale the latter undergoes hydrogenating, low temperature carbonization in a reactor, i.e. subjected to a relatively low temperature in the presence of hydrogen. In this case carbon monoxide and hydrogen, which are produced by the partial oxidation of uncondensed gaseous by-products separated from the liquid products in the process, act upon the mechanically prepared starting material, i.e. oil sand or oil shale which is mechanically reduced to a desired size, and in some cases impurities removed. In order to improve the yield of crude oil, water or steam can be additionally supplied to the reactor. A gaseous, low temperature carbonization mixture is drawn off from the reactor and subjected to condensation. In order in this process to separate out solid particles contained in the mixture, in the course of the condensation it is necessary to reduce the pressure of the low temperature carbonization mixture at the same time as it is cooled. The circulating, low temperature carbonization gas must subsequently be compressed again (U.S. Pat. No. 3 617 472).